/*
 *  Copyright 1999-2019 Seata.io Group.
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package io.seata.server.lock.distributed;

import io.seata.common.loader.EnhancedServiceLoader;
import io.seata.common.loader.EnhancedServiceNotFoundException;
import io.seata.core.store.DefaultDistributedLocker;
import io.seata.core.store.DistributedLocker;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Distributed locker factory
 *
 * @author zhongxiang.wang
 */
public class DistributedLockerFactory {

	/**
	 * The constant LOGGER.
	 */
	private static final Logger LOGGER = LoggerFactory.getLogger(DistributedLockerFactory.class);

	private static volatile DistributedLocker DISTRIBUTED_LOCKER = null;

	/**
	 * Get the distributed locker by lockerType
	 * @param lockerType the locker type
	 * @return the distributed locker
	 */
	public static DistributedLocker getDistributedLocker(String lockerType) {
		if (DISTRIBUTED_LOCKER == null) {
			synchronized (DistributedLocker.class) {
				if (DISTRIBUTED_LOCKER == null) {
					DistributedLocker distributedLocker = null;
					try {
						if (!"file".equals(lockerType)) {
							distributedLocker = EnhancedServiceLoader.load(DistributedLocker.class, lockerType);
						}
					}
					catch (EnhancedServiceNotFoundException ex) {
						LOGGER.error("Get distributed locker failed: {}", ex.getMessage(), ex);
					}
					if (distributedLocker == null) {
						distributedLocker = new DefaultDistributedLocker();
					}
					DISTRIBUTED_LOCKER = distributedLocker;
				}
			}
		}
		return DISTRIBUTED_LOCKER;
	}

	public static void cleanLocker() {
		DISTRIBUTED_LOCKER = null;
	}

}
